Fix for  #119.
Fix for  #119.

realityone/flaskbb,SeanChen0617/flaskbb,dromanow/flaskbb,lucius-feng/flaskbb,SeanChen0617/flaskbb,zky001/flaskbb,emile2016/flaskbb,realityone/flaskbb,SeanChen0617/flaskbb,China-jp/flaskbb,emile2016/flaskbb,emile2016/flaskbb,SeanChen0617/flaskbb-1,SeanChen0617/flaskbb-1,realityone/flaskbb,dromanow/flaskbb,zky001/flaskbb,zky001/flaskbb,qitianchan/flaskbb,dromanow/flaskbb,qitianchan/flaskbb,qitianchan/flaskbb,China-jp/flaskbb,SeanChen0617/flaskbb-1,lucius-feng/flaskbb,lucius-feng/flaskbb,China-jp/flaskbb